When a problem condition arises in a local area network or other subnetwork, it is generally the responsibility of the network administrator to find and rectify the problem. One of the more difficult aspects of accomplishing such a task is to specifically identify devices which comprise the subnetwork that connects the user device from which the problem was reported, to a router which interfaces with a larger network. Various software products are available to the network administrator to assist in identifying devices which populate discrete network levels.
For example, "OpenView", a software product marketed by the Assignee of this application, runs on a network administrator's work station and periodically queries routers to identify all devices that are connected to each router port. The OpenView product thus acquires, from each router, identification of hubs and switches which connect to specific router ports and the identity of the ports. The OpenView product, however, does not provide information regarding connections (or data traffic) between hub and switch ports and connected processor nodes. Further, switch to node message traffic associations are generally not considered in the construction of the association data structures within the OpenView product.
A further product of Assignee, i.e., LanProbe (with a node locator option) determines the physical layout of a segment of a network, but requires special hardware to be installed on the segment and is operational only with coaxial cabling arrangements.
U.S. Pat. No. 5,588,119 to Vincent et al. describes a method for correlating logical device names with a hub port in a local area network (LAN). More specifically, Vincent et al. describe a method for dynamically correlating the logical name of a resource with a hub port that is used for communication by the named resource. Whenever the physical topology of the network is changed, the correlation information is automatically updated. Vincent et al. indicate that their invention enables the network administrator to manage a larger number of resources and that their correlation method avoids the problem of erroneous manually created data entries.
U.S. Pat. No. 5,481,674 to Mahavadi discloses a method for generating a physical topology map of an FDDI network. Mahavadi commences by first selecting a port which feeds a controller whose external connectivity is unknown. The network management station then determines an upstream neighbor controller of the external controller that is fed by the selected port. The network management station continues, operating in an upstream manner, to determine the network topology.
There is need for a network mapping tool which enables ready identification of a network's topology between a user node and a network interface, such as a router, so as to enable fault isolation therebetween.
Accordingly, it is an object of this invention to provide an improved network mapping method and apparatus which enables ready identification and mapping of devices that are connected between a user node and a network interface device.
It is another object of this invention to provide an improved method and apparatus for deriving a subnetwork map wherein device interconnections are readily identified by a positional sort procedure to enable a path between a user node and a router to be identified.